Engine Backfiring, NO power

Ok first off its a 91 XJ with a 4.0 6cyl AW4 Auto with about 145K

So last night on Hwy-36 I drove through a decent sized puddle at speed...

No problem kept driving all the way into town without a peep..

Came out about 2 hours later and it starts hard and when you step on the gas it backfires really bad and has no power at all.. If it's in gear it backfires a bunch.. if it's in neutral it will rev up but it's very rough.

It could be coincidence but I think that puddle got something wet..

I didn't have any tools so I had to borrow a car... tonight I get to go back and take my best shot at finding something electrical that is wet and drying it..

Any guess on what could be wet and causing this or anything else I could try?

I've done a little searching and turned up a few votes for a bad TPS..

Could water cause the TPS to go bad?

Secondly this seems like the best possible time to get a GOOD service manual..

Haynes sucks this I know.. chiltons is rarely better...

What's the best service manual for these and wheres the best place to get it?

catalyic conv.

I mean oxy sensor, the one after cat, I just wasnt watching what I was typing.

You might have water under the distributor cap. Take it off, dry it out and spray it with WD-40.

Anything I can do about the water under there? Is there a seal that I'm missing?

I remember reading a post about someone prepping their jeep for water crossings talking about a ford cap that sealed better or something...

Citat3962 said:

Anything I can do about the water under there? Is there a seal that I'm missing?

Click to expand...

Pull the cap (usually they're just held in place with a couple of clips), dry it out by hand as best you can, spray in some WD-40 to expel any extra moisture (a good light coating all over the inside of the cap is about right), then clean it out a second time and let dry. Make sure there's no water in the distributor itself as well. For the amount of work this can be, particularly if you don't know the last time the cap was changed, you may as well just go get a new one and replace it outright.

I remember reading a post about someone prepping their jeep for water crossings talking about a ford cap that sealed better or something...

Click to expand...

http://www.off-road.com/jeep/fullsize/ifsjawaterproof.htm - It's for full-size Jeeps, but the basic theory's the same on pretty much anything.

Definitely check the oxygen sensor(s) as well, though... I was having similar (though less pronounced) symptoms a while back until I did mine.

Oxygen sensor has been replaced recently... like the last 6 months or so.

I went out to work on it... many miles from my tools or home.

I pulled the cap and it was pretty burnt and black on the terminals and rotor... so I replaced both and get some new plugwires as well just in case..

Still having the same problem...

I was going to try to get the distributor out but decided against it in the interest of not introducing a timing issue.. I didn't have any compressed air...

So I just limped it to friends house with a compressor and such so I could go on the water droplet hunt.. it didn't look like there was any water in it but it was dark and I didn't have a light.. so who knows it could be full of water..

I'm fairly convinced it has to be an ignition issue.. so I'll keep on that route til I'm sure it's not....

hmmmmmm.... I think firday night is going to consist of a 6 pack and an air compressor..... we'll see if I can find a puddle somewhere inconvinent..

Hows the battery and charging system doing... give it a look see.

I haven't tested for voltage output yet but it seems to be charging.. It turns the starter no problem even though I haven't really gotten to drive it far..

I'm leaning towards a bad Coil.... or whatever advances the timing...

It seems to either not have enough spark to burn the fuel when advanced... or it's not advancing...

I might just take it to a shop....

Anyone know where I can BUY a Factory Service Manual for a 91 cherokee?

bump in case someone else has an Idea for me to try out or a good place to buy an original Factory service manual.

From page 2!

Nobody knows where to get an FSM>?

Help me out here!

I searched on here and on Google and turned up NADA

Citat3962 said:

From page 2!

Nobody knows where to get an FSM>?

Help me out here!

I searched on here and on Google and turned up NADA

Click to expand...

eBAY.